I have to say this would annoy me to no end. I don't want to hear caterwauling, children crying, adults arguing, music being played so loud that it's audible across the aisle through the headphones, video games being played without headphones, or pretty much anything else outside of low murmurs of conversation on a flight. I see it as a matter of common courtesy, not everyone wants to join the reindeer games. People might not feel well (migraine, toothache, recently broken bone, etc.) or want to sleep. If they want to have ukulele flights, fine, but they should be clearly indicated in the booking process so that people can make alternate plans if they'd prefer.